Messages

1

Graphics / Re: How do I detect a mouse click on an sf:Quad in an sf::VertexArray?

« on: May 22, 2017, 07:43:42 pm »

I was able to work it out. Rather than use the modulo operator I used division to drop the remainder. Thanks for your help!

2

Graphics / Re: How do I detect a mouse click on an sf:Quad in an sf::VertexArray?

« on: May 22, 2017, 07:34:50 pm »

You can use the modulo operator:"How many times does the tile size have space in the given mouse coordinates?"

x = mouse_coords.x % tile_size.width;
y = mouse_coords.y % tile_size.height;
 

Thanks for your help, but I'm not sure how that would work.

Let's say my mouse coordinates are x(15) and y(1). Each tile is 10x10 pixels in a 100x100 pixel window. Those mouse coordinates would equal the second grid square from the left. Which is:

&tileVertices[4]

If we run that through your code it's incorrect, unless I'm misunderstanding how to use it.

// mouse_coord.x is equal to 15
// mouse_coord.y is equal to 1
// tile_size width and height is 10
x = mouse_coords.x % tile_size.width;
y = mouse_coords.y % tile_size.height;

// This calculates to (5 + 1 * 10) * 4 = 60
// This should calculate to 4
int positionInVectorArray = (x + y * numOfHorizTiles) * 4;
&tileVertices[positionInVectorArray];
 

3

Graphics / How do I detect a mouse click on an sf:Quad in an sf::VertexArray?

« on: May 22, 2017, 06:47:58 pm »

I have an sf::VertexArray of sf::Quads. As you can see by my code below, I loop through, then display them in a grid that takes up the entire window. Based on this code that determines where each tile goes into the VertexArray (0,4,8,12, etc)...

(x + y * numOfHorizTiles) * 4;

How can I determine which tile was clicked on with the x/y coordinates of a mouse click? Getting the mouse coordinates isn't a problem. The trouble is when I try to determine which tile it translates to. "x" in this sense means the number of tiles across, but the mouse click will be in pixels not tiles. So an x axis coordinate of 15 pixels could be on tile two.

for(int x = 0; x < numOfHorizTiles; ++x)
{
    for(int y = 0; y < numOfVertTiles; ++y)
    {
        sf::Vertex* quad = &tileVertices[(x + y * numOfHorizTiles) * 4];

        quad[0].position = sf::Vector2f(x * TILE_SIZE, y * TILE_SIZE);
        // etc...
    }
}

Thanks for any help.